In an online, press and poster campaign in July for T-Mobile's pay monthly price plans with inclusive internet, the company said that it offered "truly unlimited internet with no fair use policy from £25-a-month".
The small print in the ad noted that users could "only use internet on your phone in the UK and you can't use your phone as a modem (tethering) or use internet on your phone for peer-to-peer file sharing or making internet calls".
The Advertising Standards Authority received nine complaints that the claim of "truly unlimited internet" was misleading, because T-Mobile actually restricted certain activities.
Everything Everywhere, the partnership between Orange and T-Mobile, said that its £25-per-month tariff did not have a data allowance or a "fair use" policy, meaning customers were free to use as much data as they wanted without incurring extra charges or having their connections slowed.
The firm claimed that the restrictions in the small print covered "unusual types of internet activity", and the vast majority of their customers would typically use the mobile internet just for browsing.
It said that there were "commercial reasons" why internet phone calls over services such as Skype were not allowed, including the "protection" of its network.
In its ruling, the ASA said that "truly unlimited internet" was a "very strong claim" that went beyond just advertising "unlimited" internet, which most consumers understood bore some restrictions regarding usage.
The watchdog noted that T-Mobile did not impose a fair use policy on its £25-per-month package, but considered that the three restrictions imposed contradicted the "truly unlimited" claim.
"We considered that, to all intents and purposes, where an ad claimed that a plan was 'truly unlimited', exclusions would be contrary to a consumer's expectations. We therefore considered that the information in the small print contradicted the headline claim 'truly unlimited'," said the ASA.
"Because we considered that exclusions to an internet plan advertised as 'truly unlimited' would be contrary to consumers' expectations and because we understood that restrictions had been imposed on the plan, we concluded that the claim was misleading."
After finding various breaches of the Advertising Code, the ASA told Everything Everywhere that the claim "truly unlimited internet" must not appear again in its current form.
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